You select albums to add to a new or existing library with the Select Albums dialog. You get this dialog either by choosing File|New|Library or by clicking the Add button on the New/Manage Library dialog.
The Select Albums dialog contains these controls:
A list of albums in the library directory that can be added to the library. Albums already in the library aren't listed. You can select one or more by clicking, optionally with the Control and/or Shift keys held down.
If you are creating a new album and you don't see the albums you want, change the location with the Change button (see below), as you are probably in the wrong location.
The directory containing this library and the album directories for the albums it can contain. (See About Libraries for the rule about which albums can go in which albums.)
Changes the location for new libraries. Does not appear when adding albums to an existing library. Note that what albums you can add depends on the location, as described in About Libraries.
Dismisses the dialog and takes you to the New/Manage Library dialog, where the albums you've selected are listed.
Dismisses the dialog. Cancels the File|New|Library command or the Add operation, depending on how you got to the dialog.